Carcinoma of the colon is one of the most common cancers in both men and women. Man's search for qualitative differences between normal and malignant intestinal epithelial cells is complicated by the fact that malignant colonic tumors contain large numbers of fibroblasts, endothelial cells, lymphocytes, and blood cells in addition to the malignant colonic epithelial cells. Similarly, the normal precursor of the malignant intestinal epithelial cell is associated with lymphoid cells in the lamina propria, capillary endothelial cells, blood cells, muscle cells, and serosal lining cells in the normal intestine. Using methods which we have used previously for the disaggregation of tissues and for the purification of single kinds of cells, we shall develop methods for the purification of normal and malignant intestinal epithelial cells. After determining the optimal conditions for the disaggregation of tissues and for the purification of normal and malignant intestinal epithelial cells, we shall determine the best conditions for freezing and storing them over liquid nitrogen. The purified epithelial cells will be tested in several tissue culture systems in order to determine conditions which will permit the growth of normal and malignant intestinal epithelial cells. The purified cells will be tested for tumorigenicity by heterologous transplantation. The work which is described in this proposal will make colonic mucosal cells and malignant epithelial cells from intestinal carcinomas available to Dr. George Sachs who is submitting a related research proposal oriented towards the biochemical and physiologic characterization of the cells.